Epidemiologic studies of coronary risk factors have been performed primarily in populations of middle-aged adults, children, and adolscents. Relatively little is known about these risk factors in men and women 20-29 years of age. This study will prospectively examine changes in lipids, lipoproteins, and blood pressure among 295 young adults who have been followed for sixteen years in the Beaver County study. Three cross-sectional examinations have been carried out: 1) 1972-1973; 2) 1980-1981; and 3) 1988-1989. We will examine the predictors of change in total cholesterol (from examination 1 to examination 3, and change in LDL-C, HDL-C, and triglycerides between examinations 2 and 3. We will also investigate the stability in several health habits and behaviors such as cigarette smoking, alcohol use, adherence to a low fat/low cholesterol diet, and physical activity. Weight gain and oral contraceptive use have been shown in previous analyses to be strong predictors of several lipids and lipoproteins. This study should provide important insights into the determinants of CHD risk factors in young adults and may bolster the argument of those who favor the early identification of and intervention in the young coronary candidate.